Her tactic works. While they would normally be able to focus on him and drive him off, the appearance of multiple Zeuses has them confused and a little panicked. One is bad enough, but they didn't think he could duplicate himself.

Alex takes advantage of the confusion to consume dozens of soldiers. Then he stomps his feet solidly on the concrete, and sends out the extra mass that he's just gained through his feet, into the ground. Black spikes shoot up out of the concrete, tossing tanks in the air like toys, impaling soldiers and cracking the surface of the bridge.